Import into zulipchat.com

Email support@zulipchat.com with your exported archive,
the name of the Mattermost team you want to import, and your desired Zulip
subdomain. Your imported organization will be hosted at
<subdomain>.zulipchat.com.

If you've already created a test organization at
<subdomain>.zulipchat.com, let us know, and we can rename the old
organization first.

Log in to a shell on your Zulip server as the zulip user. To import with
the most common configuration, run the following commands, replacing
<team-name> with the name of the Mattermost team you want to import.

This could take several minutes to run, depending on how much data
you're importing. The server stop/restart is only necessary when
importing on a server with minimal RAM, where an OOM kill might
otherwise occur.

Import options

The commands above create an imported organization on the root domain
(EXTERNAL_HOST) of the Zulip installation. You can also import into a
custom subdomain, e.g. if you already have an existing organization on the
root domain. Replace the last line above with the following, after replacing
<subdomain> with the desired subdomain.

Logging in

Once the import completes, all your users will have accounts in your
new Zulip organization, but those accounts won't have passwords yet
(since for very good security reasons, passwords are not exported).
Your users will need to either authenticate using something like
Google auth, or start by resetting their passwords.

You can use the ./manage.py send_password_reset_email command to
send password reset emails to your users. We
recommend starting with sending one to yourself for testing:

./manage.py send_password_reset_email -u username@example.com

and then once you're ready, you can email them to everyone using e.g.

./manage.py send_password_reset_email -r '' --all-users

(replace '' with your subdomain if you're using one).

Caveats

Mattermost's export tool is incomplete and does not support exporting
the following data:

user avatars

uploaded files and message attachments.

We expect to add support for importing these data from Mattermost once
Mattermost's export tool includes them.

Additionally, Mattermost's data exports do not associated private
messages with a specific Mattermost team. For that reason, the import
tool will only import private messages for data export archives
containing a single Mattermost team.

We're here to help! Email us at support@zulip.com with questions, feedback, or feature requests.